Clutch and brake control mechanism



July 25, 1939- w. R. FREEMAN ET AL l '2,167,501

CLUTCH AND BRAKE CONTROL MECHANISM Filed June 30, 1957 F lG. l.

lam'm y uni-ngel 51- .Ef

INVENTOR.

WR. FREEMAN. B. DCYK W. 0L DT ATTORNEY.:

Patented Julyv25, 1939 UNITED STATES lCLUTCH AND BRAKE ooN'Jrnoil MEOHANISM Walter R. Freeman, University City, Burns Dick, Ferguson, and Werner F. Boldt, Overland, Mo., assignors to Wagner Electric Corporation, St. Louis, Mo., a. corporation of Delaware Application June 30, 1937, Serial No. 151,163

Claims.

Our invention relates tO improvements in means for preventing release of the brakes of a vehicle from applied position when the clutch or an equivalent mechanism is Operated to disconnect the wheels of the vehicle from the source of power,

One of the objects of our invention is to control a brake vrelease preventing means by the uid pressure in a separate fluid pressure actu- 10 ated mechanism.

A more specific Object of our invention is to so control the brake release preventing means by the pressure in apparatus for fluid actuation of the clutch mechanism,tha't the release preventing means will be permitted to be operative when the uid pressure in the clutch actuating system is sufiicient to disengage the clutch.

Other objects of our invention will become apparent from the following description taken in connection with the accompanying drawing in which Figure l is a schematic view of a fluidactuated clutch mechanism and a fluid-actuated brake mechanism showing our invention associated therewith; and Figure 2 is a cross-section- 2. al view of the control valve mechanism for preventing release of the brakes.

Referring to the drawing, the reference character I indicates the internal combustion engine of a motor vehicle which is connected through a main friction clutch 2 and a change speed gearing 3 to the wheels of the vehicle in a well-known manner. The clutch is of the usual type and comprises a clutch plate 4 splined on the gearing shaft 5 and adapted to be frictionally gnpped between a pair of clutch element-s 6 and 1 carried by the end of the engine shaft 8. The element 6 is axially movable relative to the element 1 and against the clutch engaging springs 9 (one onl, being shown) in order to permit disengagementvof the clutch, the disengaging mechanism comprising levers Il) (one only being shown), a sliding sleeve II and a clutch throwout shaft I2, all of well-known construction. The clutch throwout shaft is hydraulically actuated by the clutch pedal I3 and this mechanism consists of a compressor I4 connected by a conduit I5 with a fluid motor I6. The piston I1 of the compressor is adapted to be actuated by the clutch pedal through the medium of the piston rod I8 and the piston I9 of the uid motor is connected to actuate the clutch throwout shaft by means of the piston rod 20 and the arm 2I on the exterior end of throwout shaft I2. The piston I9 of the motor is biased against its piston rod by a light spring 22, and a spring 23 is eln- (Olt 19a- 13) A rod 21 for actuating the piston 28 of the comprcssor or master cylinder device 29 which is in communication with the fluid motors 30 of the brake assemblies 3| through the conduit 32 and branch conduits 3.2. The master cylinder is provided with a reservoir 33 which communicates with the cylinder thereof by a port 34 when the 15 piston is in its retracted position under the action of the -return spring 35.

The braking mechanism has associated therewith a control valve mechanism 36 carried by the end of the master cylinder and connected 20 with conduit 32, whereby fluid under pressure may be maintained in iiuid motors 36 of the brake assemblies vto hold the brakes applied under certain conditions. The controly valve mechanism illustrated in Figure 2 by way of example 25 is similar to that shown in Figure 6 ofthe patent to Walter R. Freeman No. 2,030,288, issued February 11, 1926. Briefly described, this mecha-` nism comprises a casing 31 having a. chamber 38 therein communicating with the master cyl- 30 inder by means of passage 39 and passage 4l through the attaching bolt 4I and also communicating with conduit 32 by a port 42. Within the chamber is a cage formed by end plates 43 and 44` and interconnecting rods 45, the lower 35 two (one only being shown in Figure 2) of which form a track for a ball 46. The end plate 43 carries an annular rubber valve seat 41 which is adapted to engage with the end wall of the chamber surrounding the open endfof passage 33 un- 40 der the action of spring 48 interposed between end plate 44 and a closure plug 49. 'I'he cage is moved in the chamber to unseat valve seat 41 by a cam 50 secured to a cross shaft 5I extending to the exterior of the casing. The casing is so at- 45 tached to the master cylinderA that the track formed by the lower rods 45 will be at a slight angle to the roadway on which the vehicle is positioned, thus insuring thaty the ball will be against seat 41 when the vehicle is on either a 50 horizontal roadway or facing upward on an inclined roadway.

In accordance with our invention, we control the valve mechanism 36 by the uid pressure in the hydraulic system for actuating the clutch u and in such a manner that the valve mechanism will be permitted to assume an operating position at the moment the clutch is disengaged and will be caused to be ineffective when the clutch elements are permitted to assume a position where they contact during their re-engaging movement. A uid motor 53 formed of a casing and a diaphragm 55 has its fluid receiving chamber connected by a conduit' 51 with conduit i5 of the clutch actuating fluid system. The diaphragm has secured thereto' a piston rod 5B which extends through a guide sleeve 59 and is connected to the arm 60 on the cage operating shaft 5l of the control valve mechanism 3G.' The guide sleeve 5S is threaded in the Wall of casing 53 of the fluid motor and interposed between it and the diaphragm is a coil spring 6l. This spring is of suflicient strength in comparison with the size of the diaphragm that when properly adjusted it will prevent the diaphragm from moving to operate arm 60 until a predetermined duid pressure is built up in chamber 56.

Referring to the operation of the above described mechanism, spring Sl is preferably adjusted by sleeve 5S so the diaphragm of fluid motor 53 will not be moved to the left until the pressure deve'oped in the clutch actuating system and chamber 56 is suicient to disengage the clutch. With this adjustment it is apparent that when the clutch pedal is depressed sufficiently to cause disengagement of the clutch, fluid motor 53 will be operated at the time of disengagement of the clutch and arm 60 rotated to the position shown in Figure 2 wherein cage 1 will be at the leftend of chamber 38 and seat 41 will be in contact with the surface surrounding passage 39. Under these conditions, if the vehicle is stopped on a horizontal roadway or facing upward on an inclined roadway, ball 46 will engage valve seat 41 under the action of gravity and the brakes, if applied, will be maintained in applied position, and if they are not applied, they may be applied by actuation of master cylinder 29 and then held in applied position. When it is desired to start the vehicle by engaging the clutch and accelerating the engine in the usual manner, the clutch pedal is released and, as a result thereof, the clutch will engage under the action of its springs 9. When the plates of the clutch contact, the pressure in the clutch actuating system and in uid motor 53 will immediately drop and the diaphragm will be free to be moved to the right under the action of spring 6|. This will cause arm 60 to be moved to the position shown in Figure 1 wherein cam 50 will move the cage to the right end of chamber 38 of-the control valve mechanism. This will cause valve seat 41 to be moved away from the surface of the end of the' chamber and iluid can then flow from the braking assemblies back to the master cylinder 23. Under conditions where the clutch is disengaged when the vehicle is moving on a roadway and the brakes are applied, the brakes will not be held in applied position due to the fact that ball l46 will not seat against valve seat 41 for the action of inertia during the deceleration of the vehicle will maintain the ball at the right end of the From the foregoing, it is readily apparent that we have devised a control means for maintaining the brakes of the vehicle in applied position when such condition is desired. 'Ihe brakes will always be released at the proper movement when the clutch is permitted to re-engage after it has been disengaged. The release of the holding amasar means is dependent upon the pressure in the clutch actuating system and with the proper setting of the adjustable spring 6I, this release will always come at thetime when the clutch plates contact. Thus it is seen that once the adjustment of spring iii is properly made, no further adjustment is necessary regardless of whether the clutch plate faces wear or not. The operation of fluid motor 53 and control valve mechanism 36 is in no way dependent upon the movement of the clutch pedal but solely upon the iiuid pressure in the clutch actuating system.

Being aware of the possibility of modifications in the particular structure herein described without departing from the fundamental principles of our invention, we do not intend that its scope be limited except as set forth by the appended claims.

Having described our invention, what We claim as new and desire to secure by Letters Patent of the United States is:

1. In a motor vehicle provided with braking mechanism, means associated with the braking mechanism for holding the brakes applied, a uid pressure system comprising an operator-controlled source of pressure and a fluid motor for operating an element of the vehicle, and means governed by fluid pressure in said system for controlling said brake holding means, said last named means being independent of said motor.

2. In a motor vehicleY provided with braking mechanism and means associated with the braking mechanism for holding the brakes applied, a iiuid' pressure system,including a fluid motor for operating an element of the vehicle, a second fluid motor for operating the brake holding means, conduit means for placing the fluid motor for the brake holding means in communication with the uid pressure system, and means whereby said last named fluid motor will be operated when the fluid pressure exceeds a predetermined value.

3. In a motor vehicle provided with braking mechanism and means for interrupting the transmission of power to the vehicle wheels, means associated with the braking mechanism for holding the brakes applied, uid pressure operated system for controlling the interrupting means and comprising an operator-controlled source of pressure and a fluid motor, and means governed by fluid pressure in said system for controlling said brake holding means, said last named means being independent of said motor.

4. In a motor vehicle provided with braking mechanism and with clutch mechanism, means associated with the braking mechanism for holdi ing the brakes applied, fluid pressure-operated means including an operator-controlled source of pressure in excess of atmospheric pressure and a fluid motor for. disengaging the clutch and permitting its reengagement, and means controlled by fluid pressure in the clutch operating means to cause said brake holding means to be operative.

5. In a motor vehicle provided with braking `mechanism and means associated with the brakmeans for varying the predetermined value of the :duid pressure necessary to operate said last named fluid motor.

6. In a motor vehicle provided with a clutch mechanism biased to clutch-engaged position by a predetermined pressure and with a braking mechanism having means associated therewith for holding the brakes applied, uid pressureoperated means including an operator-controlled source of pressure in excess of atmospheric pressure and a fluid motor for disengaging the clutch against its biasing means and permitting its reengagement, and means for operating the holding means by pressure in the uid pressure-operated means for the clutch and when said pressure is of a value to cause the clutch to be disengaged.

7. In a motor vehicle provided with a clutch mechanism biased to clutch-engaged position by a predetermined pressure and with a braking mechanism having means associated therewith for holding the brakes applied, uid pressureoperated means disengaging the clutch against its biasing means and permitting its reengagement, said means comprising a fluid motor and a source of pressure connected thereto, a uid motor for operating the holding means and in communication with the iiuid pressure-operated means o f the clutch, and means whereby said last named uid motor will be operated when the pressure in the fluid pressure-operated means for the clutch is of a value to cause the clutch to be disengaged.

8. In a motor vehicle provided with a clutch mechanism biased to clutch-engaged position by a predetermined pressure and With a braking mechanism having a brake actuating unit and a source of uid pressure connected thereto by conduit means, valve means associated with said conduit means for preventing return flow of fluid from the unit, uid pressure-operated means for disengaging the clutch mechanism against itsbiasing means and permitting its re-engagement, said means comprising a fluid motor and a source of pressure connected thereto by conduit means, a

fluid motor for operating said valve means and in communication with the conduit means of the uid pressure-operated means for the clutch, and means whereby said valve means will be operated by its operatinguid motor when the pressure in the fluid pressure-operated means for the clutch is of a value to cause the clutch to be disengaged.

9. In a motor vehicle provided with a clutch mechanism biased to clutch-engaged position by a predetermined pressure and with a braking mechanism having a brake actuating unit and a source of fluid pressure 'connected thereto by conduit means, valve means associated with said conduit means for preventing return flow of fluid from the unit, -uid pressure-operated means for disengaging the clutch mechanism against its biasing means and permitting its reengagement, said means comprising a fluid motor and a source of pressure connected thereto by conduit means, a uid motor for operating said valve means and in communication with the conduit means of the uid pressure operated means for the clutch, yieldable means for preventing the valve operating fluid motor from being operated by uid pressure except when the uid pressure exceeds a predetermined value, and means for adjusting the yieldable means to thereby vary the value of the uid pressure necessary to operate the valve operating uid motor.

10. In a motor vehicle provided with braking mechanism and with clutch mechanism, means associated with the braking mechanism for holding the brakes applied, apparatus operated by hydraulic pressure and comprising a motor for disengaging the clutch and permitting its reengagement, a motor for controlling the holding means, and connections whereby said last named motor will operate in response to the liquid pressure in the clutch operating apparatus.

WALTER R. FREEMAN. BURNS DICK. WERNER F. BOLDT. 

